Abstract:

The invention relates to a tempering chamber for tempering electronic
components, in particular, IC's, with a circulating device (15) with a
number of carrier elements (18) running in a circle and two support
devices arranged on opposite sides of the carrier elements (18) are
provided within a housing (14), wherein the carrier elements (18) are
mounted on said support elements such that the alignment of the carrier
elements (18) is unaltered on circulation.

Claims:

1-9. (canceled)

10. Temperature-control chamber for controlling the temperature of
electronic components, comprising:a housing, into which components to be
temperature-controlled can be inserted, anda holding device structured to
hold the components arranged within the housing, the holding device
comprising a plurality of bearing elements which circulate in a circular
manner and two support elements for the bearing elements which are
arranged on opposite sides of the bearing elements, wherein the support
elements consist of a first and a second spider wheel which are rotatable
about parallel but laterally offset axes of rotation and comprise rotary
arms on which the bearing elements are mounted in the diagonally opposite
corner regions thereof in such a way that the alignment of the bearing
elements remains unchanged as they circulate.

11. Temperature-control chamber according to claim 10, wherein the bearing
elements consist of rectangular bearing plates or bearing frames which
are formed to receive trays on which the components rest.

13. Temperature-control chamber according to claim 10, wherein each
bearing element is mounted on two bearings of the rotary arms which lie
in a horizontal plane in such a way that the bearing elements are
horizontally aligned.

14. Temperature-control chamber according to claim 10, wherein a loading
and removal opening for loading and removing trays is arranged in a side
region of the housing parallel to the axes of rotation of the spider
wheels.

15. Temperature-control chamber according to claim 10, wherein a removal
opening for removing temperature-controlled components vertically from
the housing is arranged on the upper side of the housing.

16. Temperature-control chamber according to claim 10, wherein the housing
comprises a loading and removal opening for trays and a removal opening
for the temperature-controlled components, in that the circulation means
stops at a plurality of circulation rest positions, and in that the
loading and removal opening for trays and the removal opening for the
temperature-controlled components are arranged adjacent to one another in
such a way that the tray from which the temperature-controlled components
are removed is, in the next circulation rest position of the circulation
means, located in the region of the loading and removal opening for
trays.

Description:

[0001]The invention relates to a temperature-control chamber for
controlling the temperature of electronic components, ICs in particular,
according to the preamble of claim 1.

[0002]Electronic components such as ICs (semiconductor components with
integrated circuits) are usually tested for their functionality before
they are mounted on printed circuit boards, for example, or used
otherwise. The components to be tested are conveyed at high speed by an
automatic handling machine, usually called a "handler", to a test device
and, following completion of the test process, are sorted depending on
the test result.

[0003]To be able to carry out the tests under predetermined temperature
conditions, it is also known to bring the components to predetermined
temperatures in a temperature-control chamber before the test process.
These temperatures may be, for example, in a range from -60° C. to
+200° C.

[0004]The temperature of the components is controlled in a convective
and/or conductive manner in an appropriately heat-insulated housing. In
the convective temperature-control process, a correspondingly
temperature-controlled air or another gas flows over the components in
the housing until they have reached the desired temperature. In the
conductive temperature-control process, the components rest on a heating
or cooling plate, by means of which heat is then transferred to or from
the component.

[0005]Controlling the temperature of the components is generally a
relatively long process since it takes a certain amount of time for the
components to be heated or cooled uniformly to the desired temperature.
This can slow the test throughput considerably. The desired high levels
of throughput frequently cannot be obtained with the known
temperature-control chambers.

[0006]The object of the invention is to provide a temperature-control
chamber of the type mentioned at the outset with which the temperature of
electronic components, ICs in particular, can be controlled in a
particularly rapid and uniform manner.

[0007]The object is achieved according to the invention by a
temperature-control chamber with the features of claim 1. Advantageous
embodiments of the invention are described in the further claims.

[0008]In the temperature-control chamber according to the invention, the
holding device arranged within the housing to hold the components has a
circulation means comprising a plurality of bearing elements which
circulate in a circular manner and two support means, which are arranged
on opposite sides of the bearing elements and to which the bearing
elements are mounted in such a way that the alignment of the bearing
elements remains unchanged as they circulate.

[0009]By using an appropriate number of bearing elements in the
temperature-control chamber according to the invention, it is thus
possible to receive and control the temperature of many components within
the housing simultaneously. The components can be loaded and removed very
efficiently and rapidly since the continued rotation of the holding
device enables the bearing element from which the already
temperature-controlled components have been removed to be brought into a
position in which it may be provided with new components to be
temperature-controlled by moving a short distance only. Furthermore, the
temperature-control process can be carried out convectively and very
uniformly within the housing since the bearing elements and the
components to be temperature-controlled are moved through the housing and
exposed to different air flows, thus avoiding any local pockets of heat
or cold.

[0010]In an advantageous embodiment, the bearing elements consist of
rectangular bearing plates or bearing frames which are formed to receive
trays on which the components rest. By using trays of this type, a large
number of components can be introduced into the temperature chamber
simultaneously, thus enabling the loading procedure to be carried out
very rapidly. The bearing elements which circulate within the temperature
chamber are in this case formed in such a way that the trays can be
simply and rapidly pushed or placed onto the bearing elements.

[0011]Special transport trays ("carrier trays") or conventional
storage/transport trays ("user trays") on which the components are
arranged individually or support means for interconnected components
("strips") for example may be used as trays.

[0012]In an advantageous embodiment, the support means are formed from a
first and a second spider wheel which are rotatable about parallel, but
laterally offset axes and comprise rotary arms on which the bearing
elements are rotatably mounted. A construction of this type enables the
desired circulation of the bearing elements, and therefore of the
components to be temperature-controlled, within the temperature chamber
to be achieved in a relatively simple manner, the bearing elements always
maintaining the desired alignment, in particular alignment in horizontal
planes. It is necessary to drive only one of the two spider wheels in
order to move the bearing elements. This may be achieved, for example, by
a drive motor which is arranged outside the temperature chamber and acts
upon one of the two spider wheels. The other spider wheel is rotationally
entrained by the bearing elements. Alternatively, drive motors which act
on both spider wheels may be provided on both sides of the temperature
chamber.

[0013]As an alternative to the two spider wheels with laterally offset
axes, it would also be possible to maintain the alignment of the bearing
elements as they circulate by mounting the bearing elements in lateral
sliding block guides which circulate in a circular manner and are
provided in the two lateral support means. In this case, the bearing
elements may also be rotated by a laterally arranged spider wheel for
example or by other drive means which act directly on the bearings of the
bearing elements. In this case, "circular" circulation may also mean that
the bearing elements circulate in an oval or approximately polygonal
circulation path.

[0014]In an advantageous embodiment, each bearing element is mounted in
the region of two diagonally opposite corners to the rotary arms. This
enables the bearing elements to be held in a particularly tilt-resistant
position.

[0015]In an advantageous embodiment, each spider wheel comprises 2 to 12,
preferably 3 to 7, rotary arms which are uniformly distributed over its
circumference, In this case, the number of rotary arms or bearing
elements expediently corresponds to the number of rest positions through
which a bearing element passes until it again reaches its original
loading position.

[0016]In an advantageous embodiment, the housing comprises a loading and
removal opening for trays and a removal opening for the
temperature-controlled components, the openings being arranged adjacent
to one another in such a way that the tray from which the
temperature-controlled components have been removed finds itself, in the
next circulation rest position of the holding device, in the region of
the loading and removal opening for trays. In this case, the portion of
the circumferential path occupied by the empty trays within the
temperature chamber is very short, whereas the trays loaded with
components may remain in the temperature chamber for a very long time
before they are removed from the temperature chamber via the removal
opening.

[0017]The invention will be described below in greater detail with
reference to drawings, in which:

[0018]FIG. 1 is a schematic view of the temperature-control chamber
according to the invention and the surrounding components which are used
to test electronic components,

[0019]FIG. 2 shows only the temperature-control chamber from FIG. 2,

[0020]FIG. 3 shows only the circulation means of the temperature-control
chamber, trays being located on the bearing elements, and

[0021]FIG. 4 is a schematic, partially exploded view of the
temperature-control chamber according to the invention comprising a
pick-and-place unit and a flipping unit for handling trays.

[0022]A possible system for testing electronic components in the form of
ICs will first be described schematically and by way of example with
reference to FIG. 1. In the figure, the arrows indicate the path of the
components.

[0023]The components are initially conveyed to a loading unit 1. The
loading unit 1 transports the components to a loading opening 2 of a
temperature-control chamber 3 (temperature chamber), in order to bring
them to the predetermined temperature within the temperature-control
chamber 3. Once the components to be tested have been brought to the
desired temperature in the temperature-control chamber 3, they are
removed from the temperature-control chamber 3 via a removal opening 5 by
a transport unit 4, which may be a pick-and-place unit for example, and
are conveyed to a central handler unit 6. The central handler unit 6
contains the means required to pick up and hold the components,
optionally means to carry out an additional component temperature-control
process, and a component displacement means to convey the components to a
test head 7 and, once the test process is complete, to remove the
components from the test head 7 once more. The central handler unit 6 may
also contain specific means to act on the components in a particular way,
for example to exert acceleration or pressure on the components or to
tilt them. The test head 7 is connected to the central handler unit 6 in
a known manner. The test head 7 is part of an electronic test device
which tests the components and evaluates the test results.

[0024]Once the test is complete, the components are removed from the test
head 7 once more by the central handler unit 6 and are conveyed by a
removal unit 8 (unloader or pick-and-place unit) to a sorting unit 9. In
the sorting unit 9, the components are sorted depending on the test
result. The components then reach a discharge station 10.

[0025]As an alternative to the embodiment shown, the temperature-control
process may also be carried out in a temperature-control chamber 3 which
is arranged completely inside the central handler unit 6. Furthermore, it
is not necessary for the components to be conveyed to the central handler
unit 6 by the transport unit 4 in the form of a pick-and-place unit, but
they may instead be conveyed by the force of gravity, as is known to the
person skilled in the art. In this case, this is achieved by what is
known as a gravity handler.

[0026]The construction and the mode of operation of the
temperature-control chamber 3 according to the invention will be
described below with reference to FIGS. 2 to 4. In this embodiment, the
temperature-control chamber 3 is constructed in such a way that it is
suitable for receiving trays 11, on which a large number of components 12
rest. These trays 11 are special transport trays, which are adapted to
the temperature-control chamber on the one hand and, on the other, enable
components to be transferred from conventional trays 13 (FIG. 4) in which
the components 12 are conveyed to the loading unit 1.

[0027]The temperature-control chamber shown in FIGS. 2 to 4 has a
heat-insulated housing 14 in which a rotatable circulation means 15 for
transporting the trays 11, and thus the components 12 placed on the trays
11, in a circular circumferential path, is arranged. The circulation
means 15 comprises two spider wheels 16, 17 and bearing elements 18 on
which the trays 11 holding the components 12 may be placed.

[0028]The two spider wheels 16, 17 are arranged in the vicinity of the two
lateral walls 19, 20 and are rotatable in parallel vertical planes. The
first spider wheel 16 is rotatable about a first axis of rotation 21,
whereas the second spider wheel 17 is rotatable about a second axis of
rotation 22. The two axes of rotation 21, 22 extend horizontally and
parallel to one another, but are offset laterally by a distance a. The
spider wheels 16, 17 are supported by stub shafts 23, 24 which are
rotatably mounted in bearing brackets 25, 26.

[0029]The bearing brackets 25, 26 may be integrated into the lateral walls
19, 20 or arranged separately therefrom in the direct vicinity of the
lateral walls 19, 20. Care should be taken to ensure that the stub shafts
23, 24 extend inwards only up to the respective spider wheel 16, 17, each
spider wheel thus only being mounted on one side.

[0030]As can be seen in FIGS. 2 and 3 in particular, the spider wheel 17
is set into rotation by a drive motor 27, a drive belt 28 and a belt
pulley 29 which is rotationally coupled to the stub shaft 24 which
penetrates the lateral wall 20. The other spider wheel 16 is rotationally
entrained by the bearing elements 18. In this way, the two spider wheels
are rotated synchronously with one another in the same direction of
rotation in a very simple manner. Alternatively, it is also possible to
drive the two spider wheels 16, 17 synchronously by using drive motors.

[0031]In the present embodiment, the spider wheels 16, 17 comprise five
rotary arms 30 which are of the same length, extend radially outwards
from the centre of the spider wheels 16, 17 and are distributed regularly
over the circumference of the spider wheels 16, 17.

[0032]The bearing elements 18 are arranged horizontally between the two
spider wheels 16, 17. The bearing elements 18 consist of rectangular
bearing plates or frames, the size of which in the embodiment shown is
only slightly larger than that of the trays 11 resting thereon. As shown,
the diagonally opposite corner regions of the bearing elements 18 are
rotatably mounted in the free end region of the rotary arms 30 of the
first spider wheel 16 on the one hand and in the free end region of the
rotary arms 30 of the second spider wheel 17 on the other. Since the
rotational positions of the two spider wheels 16, 17 are aligned with one
another in such a way that the rotary arms 30 of the two spider wheels
16, 17 assume the same angular position and also since the two axes of
rotation 21, 22 of the spider wheels 16, 17 are located adjacent to one
another and offset in a horizontal plane, the trays 11 are always held in
horizontal planes in any rotational position of the spider wheels 16, 17.
The number of bearing elements 18, and therefore the number of the trays
11 which can be arranged thereon, thus corresponds to the number of
rotary arms 30 of each spider wheel 16, 17. If the spider wheel 16 is
rotated in the direction of the arrow 31 about the axis 21 and the spider
wheel 17 is rotated in the direction of the arrow 32 about the axis 22,
the bearing elements 18, and thus the trays 11 arranged thereon, are
moved through the temperature-control chamber without the horizontal
alignment of the trays 11 being affected.

[0033]As shown, the drive motor 27 and the belt pulley 29 are arranged
outside the housing 14. It is therefore only necessary to guide the stub
shaft 24 through the lateral wall 20 of the housing 14 and to form said
stub shaft 24 in such a way that it is long enough for the belt pulley 29
to be fastened thereto.

[0034]As can further be seen from FIG. 2, the lateral wall 20 of the
housing comprises a lateral loading and removal opening 33 to enable the
trays to be loaded and removed parallel to the axes of rotation 21, 22 of
the spider wheels 16, 17. The loading and removal opening 33 (which
corresponds to the loading opening 2 in FIG. 1) is located in an upper
region, i.e. in the relative vicinity of the upper closing wall of the
housing 14 containing the removal opening 5 (FIG. 1) through which the
temperature-controlled components 12 can be removed and conveyed to the
central handler unit 6.

[0035]A horizontally-aligned transfer plate 34 on which the trays 11 can
be placed, as described in greater detail below with reference to FIG. 4,
extends horizontally outwards from the lateral loading and removal
opening 33. The transfer plate 34 thus represents a laterally projecting
loading ramp, by means of which the trays 11 can be introduced into the
temperature-control chamber. In this process, the trays 11 are guided in
guide grooves 35 which are provided on the upper side of the transfer
plate 34 and of the bearing elements 18 in the vicinity of, and along,
the lateral edges thereof Guide webs 36, located on the lower side of the
trays 11 along the lateral edges thereof engage in these guide grooves
35.

[0036]In the position shown in FIG. 2, a rear bearing element 18a is
located at exactly the same height as the transfer plate 34 and is
aligned therewith in such a way that a tray 11 placed on the transfer
plate 34 can be pushed from said transfer plate 34 into the interior of
the housing 14 onto the bearing element 18a. In the same way, an empty
tray 11, after it has passed through the temperature-control chamber 3
and the temperature-controlled component 12 has been removed from above
via the removal opening 5, can be removed laterally from the
temperature-control chamber 3 when the bearing element 18a with the empty
tray 11 is aligned with the transfer plate 34.

[0037]As can further be seen from FIG. 2, two radiant heaters 37 and a
further electric heating means 37a for producing the required temperature
within the housing 14 are arranged in the base region of the
temperature-control chamber 3 below the circulation means 15. A drum fan
38, which is also arranged in the base region of the temperature-control
chamber 3 and extends over the majority of the width of the housing 14,
ensures that the air heated by the radiant heaters 37 is distributed
uniformly within the temperature-control chamber 3.

[0038]The mode of operation when loading and unloading the
temperature-control chamber 3 will be described in greater detail below
with reference to FIG. 4.

[0039]The components 11 which are to be temperature-controlled and
subsequently tested initially rest in conventional trays 13 which are
arranged on top of one another in the form of a stack. An empty tray 11
(transport tray) is placed on the stack 39 by a flip unit 40 in order to
lift the top tray 13, together with the components 11 located therein,
off the stack. The flip unit 40 rotates the tray 11, together with the
tray 13 held thereagainst, upwards by 180° about a horizontal
axis, as indicated by the arrow 41. The tray 13 is now upside down above
the transport tray in such a way that the components 11 fall onto the
transport tray 11. The now empty tray 13 is grasped by a pick-and-place
device 42 arranged thereabove and is moved laterally in the direction of
the arrow 43 and then placed laterally adjacent to the stack 39 in the
direction of the arrow 44, thus forming a stack 45 of empty trays 13. For
this purpose, the pick-and-place device 42 comprises, as is known in
principle, a retaining head 46 which can be displaced in two orthogonal
horizontal directions and in the vertical direction and optionally may
also be rotatable about at least one axis.

[0040]The transport tray 11 which is held, together with the components
11, by the flip unit 40 in the raised position which is aligned with the
plane of the transfer plate 34 is pushed by a device (not shown in
greater detail) onto the transfer plate 34, as indicated by the arrow 47.
From there, the transport tray 11 is pushed by a transport device (not
shown in detail) into the interior of the housing 14 and onto the bearing
element 18a which is positioned at the same height as the transfer plate
34.

[0041]The circulation means 14 is at that point caused to circulate by the
drive motor 27 in such a way that the bearing element 18a, together with
the tray 11 located thereon, rotates downwards by an angle of rotation of
72° (1/5 of 360°). In this first rest position, the
adjacent bearing element 18b which previously was located in the highest
position in the region of the removal opening 5, is now positioned at the
same height as the transfer plate 34. An empty transport tray 11 which
may be present on this bearing element can at this point be pushed
laterally out of the housing 14 onto the transfer plate 34. From there,
the tray can be brought into the engagement region of the flip unit 40
and be lowered thereby onto a full tray 13 on the stack 39 in order to
raise the tray 13 filled with components 12 as previously described and
to convey the transport tray 11, together with the not yet
temperature-controlled components 11, to the transfer plate 34 and from
there onto the waiting empty bearing element 18. The circulation means 15
is then rotated again by a 72° step, where the described
procedures of removing and loading a transport tray 11 through the
lateral loading and removal opening 33 are repeated.

[0042]By rotating the circulation means 15 in steps in the direction of
the arrow 31, each bearing element 18 reaches the region laterally
adjacent to the transfer plate 34 in such a way that it can be loaded
with a transport tray 11 filled with components 11. Once a loaded bearing
element 18 has covered 4/5 of its entire circulation path, it is located
in its highest position directly below the removal opening 5 located in
the cover portion of the housing 14. This uppermost bearing element is
provided with the reference numeral 18b in FIGS. 2 to 4. The components
12 resting on the associated tray 11 can at this point be lifted by the
transport unit 4 (pick-and-place unit) in the direction of the tray 48
and conveyed to the central handler unit 6 (FIGS. 1 and 4).

[0043]Since the removal position of the components 11 is directly before
the loading position in the temperature-control chamber 3 in the
direction of circulation of the circulation means 15, the emptied tray 11
must only be rotated further by a very small distance, namely 72°,
in order to return to the loading position. The vast majority of the
circulation path is thus available to control the temperature of the
components 11. A further advantage is that the uppermost bearing element
18b is able, together with the tray 11 resting thereon, to close the
upper removal opening 5 almost fully so the flow of heat through the
removal opening 5 while the components 12 are removed can be minimised.
Furthermore, the lateral loading and removal opening 33 can be kept very
small and preferably closed by a slide or shutter mechanism so that the
loss of heat through this loading and removal opening 33 can also be
minimised.